Fluid flow control mechanism



Sept. 17, 1968 Filed June 9, 1966 N. L. ADSIT FLUID FLOW CONTROLMECHANISM 3 Sheets-Sheet 1 M 7 #4 H] INVENTOR ATTORNEY Sept. 17, 1968 N.L. ADSIT FLUID FLOW CONTROL MECHANISM 3 Sheets-Sheet 2 Filed June 9,1966 INVENTOP ATTORNEY Sept. 17, 1968 N. L.'ADSIT 3,401,872v

' FLUID FLOW CONTROL MECHANISM Filed June 9, 1966 3 Sheets-Sheet 5INVENTOP Harman .6. fldsd di /aw ATTORNEY United States Patent 3,401,872FLUID FLOW CONTROL MECHANISM Norman L. Adsit, Saginaw, Mich., assignorto General Motors Corporation, Detroit, Mich., a corporation of DelawareFiled June 9, 1966, Ser. No. 556,492 1 Claim. ((31. 230-157) ABSTRACT OFTHE DISCLOSURE A vane pump supplies air for injection into the exhaustgases of an internal combustion engine. The pump rotor has a metal bodyformed by extrusion and includes a molded-in-place reinforcedthermo-plastic liner providing a vane driving surface and a support fora vane bearing follower shoe.

This invention relates to fluid flow control mechanism especially usefulin a system for injecting air into internal combustion engine exhaustgases to promote combustion of unburned exhaust gas constituents.

In the recent past increasing emphasis has been placed on reducing theproportion of unburned constituents, such as unburned hydrocarbons andcarbon monoxide, present in the exhaust gases emitted from automotiveengines. One of the most elfective arrangements devised to accomplishthis reduction is the Air Injection Reactor system. In this system, anengine driven pump injects a stream of air into the flow of hot exhaustgases as they are emitted from the engine combustion chambers. Utilizingthe heat of the exhaust gases, the injected air supports additionalburning of the exhaust gases in the engine exhaust passages to reducethe proportion of unburned exhaust gas constituents.

The requirements imposed upon the pump used to supply the air in the AirInjection Reactor system are quite stringent; for example, the pressureand the rate of air flow from the pump must be carefully controlled overa wide range of engine and vehicle speeds. It has been discovered that asemi-articulated vane pump is a very eflicient and economical type forsuch an application.

An object of this invention is to provide improved fluid flow controlmechanism which is especially useful in providing air flow at properlyregulated pressures and rates in an Air Injection Reactor system.

More particularly, one feature of the improved fluid fluid controlmechanism disclosed herein is a combination, useful in an air pump, of arotor disposed within a stator to form a working chamber in which theexterior surface of the rotor is provided with an abradable surfacecoating which seals the working chamber both at its ends and in the areabetween the working chamber inlet and outlet.

In an additional feature, the fluid flow control mechanism shown hereinincludes a rotor formed by impact extrusion and adapted to guideaplurality of vanes through a working chamber in which the rotor containsan inserted liner supporting vane bearing shoes. Two embodiments of sucha liner are disclosedone being fabricated, and the other being molded inplace.

As a further feature the fluid flow control mechanism disclosed hereinincludes a vane molded about a counterweighted hub.

As another feature, the fluid flow control mechanism disclosed hereinincludes a rotor accurately aligned within a stator and retained inaligned position by material "ice injected about the outer race of aball bearing unit, the inner race of which is secured to the rotor.

In addition, the fluid flow control mechanism disclosed herein has as afeature a rotary air cleaner secured to a pump rotor drive shaft.

Further, the fluid flow control mechanism disclosed herein includes as afeature small vane shoes forming bearing surfaces at each end of thevanes.

Even further, the fluid flow control mechanism disclosed herein has as afeature wedge-shaped openings between the bases of the vane drive andfollower bearing strips and their supporting members which reduce noiseattributed to the bearing strips.

Moreover, the fluid flow control mechanism disclosed herein has as afeature a construction of the stator end wall which allows a pulleysupporting hub to be assembled on the rotor drive shaft before the rotoris assembled within the stator.

Furthermore, the fluid flow control mechanism disclosed herein has as afeature a regulating valve means which prevents excessive air flow tothe engine exhaust system. This regulating valve means includes apressure relief valve to divert a portion of the air flow at high speedsand additionally includes an engine vacuum operated actuator to divertthe air flow through the relief valve during vehicle deceleration.

The details as well as other objects and advantages of this inventionare disclosed in the following description of a preferred embodiment ofthis fluid flow control mechanism as shown in the drawings in which:

FIGURE 1 is a view of an automotive vehicle internal combustion engineprovided with a pump which injects air into the exhaust system and withregulating valve means therefor;

FIGURE 2 is an axial sectional view through the pump and its outletchamber illustrating the rotor sealing locations, the rotor alignmentconstruction, the air cleaner, the vane end bearing shoes, the statorend Wall construction, and the regulating valve means;

FIGURE 3 is a sectional view along line 3-3 of FIG- URE 2 illustratingthe vane and fabricated rotor liner constructions;

FIGURE 4 is an enlarged sectional view along line 44 of FIGURE 3illustrating the air flow path from the air cleaner to the pump inletchamber;

FIGURE 5 is an enlarged view of a portion of FIG- URE 3 illustrating thewedge-shaped clearance between the vane follower bearing strip and itssupporting construction;

FIGURE 6A is an enlarged view of a portion of the molded rotor linerillustrating the drive bearing surface provided for the vane and alsoillustrating an alternative construction for achieving the wedge-shapedclearance between the vane follower bearing strip and its support;

FIGURE 6B is an enlarged view of another portion of the molded rotorliner illustrating the bearing surface provided for the end of the vane;

FIGURE 7 is an enlarged sectional view along line 77 of FIGURE 2illustrating the pressure relief valve;

FIGURE 8 is an enlarged sectional view of the engine vacuum operatedrelief valve actuator showing the actuator in normal position;

FIGURE 9 is a view similar to FIGURE 8 showing the actuator in valveoperating position;

FIGURE 10 is a sectional view along line 10-10 of FIGURE 8 furtherenlarged to show details of a timing valve mechanism; and

3 FIGURE 11 is a sectional view along line 11-11 of FIGURE illustratingfurther details of the timing valve. Referring first to FIGURE 1, aninternal combustion .engine E is provided with a carburetor C whichforms a combustible mixture for delivery to the combustion chambersthrough an intake manifold M. An air filter F provides clean air forcarburetor C. An air pump 10 is secured to engine E by a bracket 12 andis driven from engine E by a belt 14. Air pump 10 has an outlet hose 16through which air is delivered to an air manifold 18. Air manifold 18has a series of injection tubes 20 through which air is injected intothe stream of exhaust gases leaving the engine combustion chambers.

Referring now to FIGURES 2 and 3, air pump 10 has a concave housing 22closed by a cover plate 24. As shown in FIGURE 3, the interior wall 26of housing 22 is of circular cross-section. A rotor 28, disposed inhousing 22 on an axis eccentric to the axis of the housing, has anexterior wall 30 of circular cross-section which is tangent the interiorwall 26 of housing 22 at its lowermost point to provide a stripping land32.

Housing 22 is an aluminum casting and rotor 28 is a steel impactextrusion so that, as the temperature of the pump increases duringoperation, housing 22 will expand faster than rotor 28 to preventinterference between these two parts.

The interior Wall 26 is recessed on opposite sides of the stripping land32 to form an inlet chamber 34 and an outlet chamber 36. A particularadvantage is achieved by locating the inlet and outlet chambers 34 and36 at the bottom of the pump since any moisture tending to condense inthe pump will drain into these areas. Should the pump be mounted in aninverted position, the moisture would drain to another portion of thehousing and, were it to freeze, would interfere with pump operation.

A shaft 38 is secured in cover plate 24 and extends into housing 22concentrically with the interior wall 26. Two pairs of bearingsupported, counter-weight hubs 40 are positioned on shaft 38. Aroundeach pair of hubs 40 is molded a vane 42 which locks into the hubs 40 asshown at 44 in FIGURE 3.

Each vane 42 extends out to the interior wall 26 of the housing 22. Asshown in FIGURE 3, the tips of vane 42 are provided with a curved recess46. The vanes are molded from a thermo-setting plastic resin reinforcedwith random glass or asbestos fibers and are constructed to contactinterior wall 26. During initial running of the pump the tips of thevane 42 abrade on the interior wall 26, thus forming a slight clearancebetween vanes 42 and wall 26. This slight clearance reduces thefrictional resistance of the pump but does not seriously reduce itspumping efiiciency.

Rotor 28 surrounds shaft 38 and hubs 40 and is provided with slots 48through which vanes 42 extend. Rotor 28 has an integral shaft 50extending through an end wall 52 of housing 22. A hub 54 is pressed ontoshaft 50, and a pulley 56 is bolted to hub 54. Pulley 56 may beinterchanged with other pulleys of different diameters to providevariousrotor speeds for the same engine. As rotor 28 is driven by engine Ethrough belt 14, pulley 56, hub 54, and shaft 50, vanes 42 are sweptthrough the crescentshaped working chamber 58 (counter-clockwise asviewed in FIGURE 3) to draw air from inlet chamber 34 and direct apressurized stream of air into outlet 36. Stripping land 32 preventsleakage of air between outlet chamber 36 and inlet chamber 34.

As shown in FIGURE 3, the interior wall 26 of housing 22 is providedwith notches 60 between the working chamber 58 and the inlet and outletchambers 34 and 36. Notches 60 prevent sudden change in pressure asvanes 42 pass the inlet and outlet chambers 34 and 36 and contribute tosmooth and quiet operation of the pump.

As shown in FIGURE 2, end wall 52 of housing 22 and cover plate 24 areprovided with interior recesses 62 and 64 into which the ends of rotor28 extend. Shoul ders 66 and 68 in the recesses 62 and 64 seal on theexterior wall 30 of the rotor 28 to close the ends of the workingchamber 58. An abradable surface coating, such as a coating containingmolybdenum disulfide, is applied to the entire surface of exterior Wall30 to enhance the sealing and provide a bearing surface at the ends ofthe working chamber on shoulders 66 and 68 and between the inlet andoutlet chambers 34 and 36 at the stripping land 32.

As shown in FIGURES 2, 3, and 4 with specific reference to FIGURE 3,metal liners 70 are spot welded within rotor 28. Liners 70 are formedinto outwardly extending recesses at 72 and are provided with slots 74through which the vanes 42 extend. The recessed liners 70 providechannels adjacent the slots 48 in the rotor which support carbon driveand follower bearing shoe strips 76 and 78. Leaf-type springs 80 biasfollower shoes 78 against the vanes 42. Strips 76 and 78 provide abearing surface for the vanes 42 and close slots 48 to seal workingchamber 58 from the interior of rotor 28.

Slots 74 do not extend the entire axial length of the recessed liners 70and rotor 28 but rather terminate short of the ends to provide straps 82adjacent each end of vanes 42. Straps 82 retain small arcuate carbonshoe strips 84 (shown in section in FIGURE 2) at each end of vanes 42 toprovide bearing surfaces at each end of vanes 42.

Referring to FIGURE 3, it will be noted that counterweight hubs 40 areasymmetrically curved at 85. This curvature allows the vane and hubassemblies to be inserted Within the rotor 28 and the tips 46 of thevanes 42 inserted through slots 74 in the recessed liners 70, subsequentto which shaft 38 is inserted through the bearings in hubs 40.

Dowels 86 are held in place by liner 70 and as shown in FIGURE 2 arebottomed against the closed end of rotor 28. Dowels 86 provide areference point to which a cap 88 may be pressed to enclose the open endof rotor 28. Cap 88 forms a bearing mounting surface for a rollerbearing 90.

As illustrated in FIGURE 5, a wedge-shaped clearance is provided beneaththe vane drive and follower bearing shoes 76 and 78 to prevent asqueaking noise attributed to movement of the shoes in the channel. Thiswedgeshaped clearance may be provided by inclining the base 92 of theshoes at a slight angle a relative to the sides 94 of the shoes, oralternatively, by inclining the follower springs 80 or the base of thechannel.

FIGURES 6A and 6B illustrate an embodiment in which the rotor liner ismolded in place rather than fabricated. Molded liner 96 covers theentire inner surface of the rotor 28 and is formed with vane followerbearing shoe and spring supporting channels 98. As indicated in FIGURE6A, the base 100 of channels 98 may be inclined at an angle a relativeto the sides 102 to create a wedge-shaped clearance space beneath theshoes. Thermosetting plastic resins, particularly phenolics, reinforcedwith strands of fiberglass or asbestos have been found particularlysatisfactory as liner materials. With such materials the liner mayprovide a direct bearing surface for vanes 42, eliminating the necessityfor vane drive shoes 76 and at least one set of vane end shoes 84. Whenthese shoes are eliminated, liner 96 bears directly against vanes 42 atthe contoured portion 104 indicated in FIG- URE 6A and directly againstthe end of vanes 42 as indicated in FIGURE 6B.

Referring now to FIGURE 2, a set of ball bearings 108 are pressed onshaft 50 prior to assembly of rotor 28 within housing 22 and the rotoris then accurately aligned within housing 22 between the ends of therecesses 62 and 64. A plastic material is then injected through openings110 into an annular space 112 about the bearing 108. Upon hardening, theplastic in the annular space 112 maintains rotor 28 against axialmovement within housing 22.

Still referring to FIGURE 2, it will be noted that end wall 52 ofhousing 22 has an opening 113 sufficiently large that hub 54 may passtherethrough. This allows hub 54 to be pressed on shaft 50 prior toassembly of rotor 28 within housing 22 and prevents damage which mightotherwise occur were hub 54 to be pressed on shaft 50 after assembly.

An air cleaner 114 is secured about hub 54. Air cleaner 114 includes aplurality of radially directed passages 116 which connect with axiallydirected apertures 118. Apertures 118 open into an annular recess 120 onthe outside of end wall 52 of housing 22. A lip 122 on air cleaner 114seals the open end of recess 120. As shown in FIG- URE 4, a passage 124connects annular recess 120 with the inlet chamber 34. During operationof the pump, air flows radially through openings 116 and apertures 118into recess 120 and from there through passage 124 into inlet chamber34. The construction of cleaner 114 is such that it centrifuges out dustparticles and other foreign material and permits only clean air to bedrawn into the pump.

Referring now to FIGURES 2 and 7, a pressure relief valve 126 is pressedinto an opening in the side wall 128 of exhaust chamber 36. Pressurerelief valve 126 includes a cup-shaped member 130 having an opening 132from chamber 36. The base 134 of member 130 forms a valve seat for aplate-type valve member 136. Valve member 136 is biased against the base134 by a spring 138 seated in spring seat members 140 and 142. It willbe appreciated that the force of spring 138 may be controlled byadjusting the configuration of seat member 142 so that the axialdistance between seat member 142 and base 134 is varied. Valve member136 is lifted off base 134 against the bias of spring 138 by pressuresin outlet chamber 36 above a predetermined minimum. Thus the pressurerelief valve 126 diverts air from outlet chamber 36 during high enginespeeds (which cause high pump speeds and consequent high pressure) whenthe rate of air delivered by the pump is not required or desirable inthe exhaust system.

Referring to FIGURE 2, it will be noted that outlet chamber 36 is formedby a first chamber portion 144 and a second chamber portion 146. Afitting 148 extends from outlet chamber portion 146 and has hose 16connected thereto which, as shown in FIGURE 1, directs air into the airmanifold 18.

During deceleration of the vehicle, the exhaust contains a highproportion of unburned constituents. When air is added during a suddendeceleraion of the vehicle, a mixture is formed which is susceptible toexplosion or backfire. In order to avoid such, an actuator 150 isadapted to prevent the flow of air from outlet chamber portion 144 tooutlet chamber portion 146 and at the same time to divert the air flowdelivered by the pump through the relief valve 126. Actuator 150 andrelief valve 126 form a regulating valve means which prevents injectionof air into the exhaust gas during deceleration.

As shown in FIGURE 2, a valve seat 152 is formed between outlet chamberportions 144 and 146. A valve member 154 formed on the actuator plunger156 cooperates with valve seat 152 to prevent air flow fro-m outletchamber portion 144 to outlet chamber portion 146. Simultaneously,plunger 156 actuates a stem 158 secured to relief valve member 136 toopen the relief valve.

When air is discharged from relief valve 126 at low vehicle speeds, itis desirable that the noise of air flow therethrough be silenced. Thisis accomplished by connecting a hose 160 to relief valve 126 so that allair flow from valve 126 is directed to the combustion air filter F asindicated in FIGURE 1. Alternatively, separate silencing means may beincluded as a component of the relief valve 126.

FIGURES 8 through 11 illustrate an embodiment of the actuator 150.Actuator 150 includes first and second housing members 162 and 164clamped about a flexible pressure responsive diaphragm 166 to form apair of chambers 168 and 170. Chamber 168 has a fitting 172 by whichconnection is made through a hose 174 to a source of engine vacuum suchas the intake manifold M, as shown in FIGURE 1. During enginedeceleration, engine vacuum is sufficient to overcome the force of aspring 176 and pull diaphragm 166 to the right as viewed in FIG- URES 8and 9. A member 178, secured to diaphragm 166, carries plunger 156 whichoperates valve 154 and, through stem 158, valve 126. Thus, during enginedeceleration, air is not injected into the exhaust system but rather isdiverted into the engine air filter F.

Since it is desirable that diversion of the pump air delivery occur foronly a predetermined interval, actuator is provided with means, fortiming the subsequent opening of valve 154 and closing of valve 126.Member 178 has an opening 180 extending from chamber 168 to chamber 170.A small plate-like valve member 182, shown best in FIGURE 11, controlsair flow through opening 180 to and from chamber 170. When high enginevacuum is applied to chamber 168, valve member 182 senses the pressuredifferential between chambers 168 and at opening and closes the opening.A restricted bleed 184 through valve 182 allows emptying of chamber 170within a predetermined interval. When the pressure in chamber 170approaches that within chamber 168, spring 176 moves the diaphragm 166and plunger 156 to the left as viewed in FIGURES 8 and 9, opening valve154 and closing valve 126 to permit delivery of air to the exhaustgases. If, before chamber 170 is emptied, the carburetor throttle isagain opened, the pressure in chamber 168 rises and valve 182 moves awayfrom opening 180. A plurality of large openings 186 allows the pressurein chamber 170 to be raised instantly to the pressure in 168 so thatdiaphragm 166 and plunger 156 move to the left, quickly opening thevalve 154 and closing valve 126.

It will be appricated that many features of the fluid flow controlmechanism shown and described herein are useful in environments quitedifferent from the Air Injection Reactor system. It should also beappreciated, however, that in the Air Injection Reactor system, thisfluid flow control mechanism dependably and efficiently provides airflow at proper pressures and rates to effectively control exhaustemissions over a wide range of engine and vehicle speeds.

I claim:

1. A rotary mechanism comprising a housing having a cylindrical internalperipheral wall forming a cavity, a hollow rotor eccentricallypositioned within said cavity and having a cylindrical externalperipheral wall radially spaced from at least a portion of said internalperipheral wall to form a working chamber, a shaft extendingconcentrically into said cavity, said shaft being surrounded by saidrotor, at least one radially extending vane mounted for rotation uponsaid shaft, said rotor having a slot through which said vane extendsinto said working chamber, said rotor and vane being adapted uponrotation to direct a fluid stream through said working chamber, andwherein said rotor has a cylindrical internal peripheral surface and aone-piece liner of glass fiber reinforced thermosetting plastic resinmolded therewithin to cover said surface, said liner having an extensionprojecting radially outwardly through said slot about said vane andterminating adjacent said external peripheral wall of said rotor, saidliner having a wall defining an aperture which opens through said slotand through which said vane extends, said aperture wall directlyengaging at least one surface of said vane to provide a bearing surfacetherefor, said liner further having an axially reaching extensionprojecting radially inwardly and forming an axially reaching channelopening toward said vane, a vane bearing shoe strip supported in saidchannel, and a leaf spring disposed in said channel beneath said stripand biasing said strip into engagement with the adjacent surface of saidvane to provide a bearing surface therefor.

(References on following page) 7 8 References Cited 3,132,632 5/1964Kehl 230157 X 3,185,102 5/1965 Partain et a1 103144 UNITED STATESPATENTS 3,322,335 5/ 1967 Partain 230-157 9/1932 Moore 103144 11/1934Higbee 230157 N 11/1938 Mabine 103144 a FRED C. MATTER JR., PrimaryExammer.

5/ 1949 Shorrock 230-457 W. J. KRAUSS, Assistant Examiner. 1/1963 Weiss103-144

